Hepatitis A has continued to spread in southeast Michigan with 319 confirmed cases between Aug. 1, 2016 and Sept. 15 — resulting in 14 deaths, state health officials announced Thursday.

The cases in Detroit and Wayne, Oakland, Macomb, Monroe and St. Clair counties represent a 16-fold increase over the same period in 2014-15.

Eighty-one cases were diagnosed last month alone, compared with six reported to the Michigan Department of Health and Human Services in August 2016.

“The southeast Michigan hepatitis A outbreak remains a top priority for public health officials from both the investigation and prevention standpoints,” Dr. Eden Wells, chief medical executive for MDHHS, said in a press release Thursday.

“Hepatitis A is a vaccine-preventable disease and in addition to our investigation of current and new cases, our focus is strongly aimed at increasing vaccination in adults, where hepatitis A vaccination is commonly low.”

Health officials have doubled down on efforts to fight the outbreak through increased awareness. The highly contagious viral liver disease can sometimes cause liver failure and death, but is easily prevented by getting vaccinated.

The state agency said no common source of the outbreak, such as contaminated food or water, has been identified. Transmission appears to be person-to-person, mostly through illicit drug use, sexual activity and other close contact.

MDHHS sent a letter to 5,069 Medicaid-enrolled health care providers across southeast Michigan earlier this month with information about the outbreak and the need for people to get vaccinated.

They said many vaccination campaigns are in place across the region, with some focusing on high-risk populations at jails, substance use treatment centers and homeless centers.

DHHS also has been in discussions with the Michigan Department of Corrections about implementing a vaccination campaign in the Detroit Receiving Center and Detroit Detention Center, they said.

Local health departments also are partnering with community organizations to provide hepatitis A vaccine to at-risk individuals, officials said. More than half of those diagnosed have a history of substance abuse, and 15 percent are homeless or living in shelters, according to DHHS.

Individuals with hepatitis A are infectious for two weeks before symptoms appear. The symptoms include jaundice (yellowing of the skin), fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine and light-colored stools.

People most at risk are those living with someone who has hepatitis A, having sexual contact with someone who has hepatitis A, or sharing injection or non-injection illegal drugs with someone who has hepatitis A. The virus also can be transmitted through contaminated food or water.